Water Quality

The Nation's rivers and streams are a priceless resource, but pollution from urban and agricultural areas pose a threat to our water quality. To understand the value of water quality, and to more effectively manage and protect the Nation's water resources, it's critical that we know the current status of water-quality conditions, and how and why those conditions have been changing over time.

Water and the chemicals it contains are constantly being exchanged between the land surface and the subsurface. Surface water seeps into the ground and recharges the underlying aquifer—groundwater discharges to the surface and supplies the stream with baseflow. USGS Integrated Watershed Studies assess these exchanges and their effect on surface-water and groundwater quality and quantity.

Saltwater intrusion has occurred to some degree in many of the coastal aquifers of the United States. Since saltwater cannot be used to irrigate crops or be consumed by people, saltwater intrusion can be very problematic to coastal communities that rely on fresh groundwater supplies for the livelihood. The USGS studies how excessive groundwater pumping, sea level rise, and other factors contribute...

Hydraulic fracturing, commonly known as fracking, is the process of injecting water, sand, and/or chemicals into a well to break up underground bedrock to free up oil or gas reserves. The USGS monitors the environmental impact of this practice across the country, from potential earthquakes to degraded groundwater quality.

The USGS Quality Systems Branch (QSB) represents the Water Resource Mission Area’s commitment to generating environmental data of known quality. QSB produces water and sediment performance-assessment samples and data to provide the USGS laboratory users, USGS laboratories, and field personnel with quantitative performance information to assess data quality.

USGS Cooperative Matching Funds (CMF) support joint projects with our state, regional, tribal, and local partners to provide reliable, impartial, and timely information needed to understand and manage the Nation's water resources.

Intensive studies by the USGS National Water-Quality Assessment (NAWQA) Project in agricultural areas provide insight into how agricultural activities have altered the natural flow of water and the way that agricultural chemicals enter streams and aquifers, and in particular how nutrients affect algal and invertebrate communities in agricultural streams.

The USGS has been at the forefront of studying the impacts of acid rain for decades. How does acid rain form? What does it do to the landscape? Can it burn you like battery acid? Keep reading to find out more...

All natural waters contain some dissolved solids (salinity) from contact with soils, rocks, and other natural materials. Too much, though, and dissolved solids can impair water use. Unpleasant taste, high water-treatment costs, mineral accumulation in plumbing, staining, corrosion, and restricted use for irrigation are among the problems associated with elevated concentrations of dissolved solids.

Oil spills, such as the 2010 Deepwater Horizon Oil Spill, are impactful environmental disasters that have long lasting effects to the landscape, native species, and inhabitants who depend on the area. The USGS explores the adverse effect that large-scale oil spills have on the environment and helps responders prepare for environmental recovery and rehabilitation.

Pesticides are chemicals designed to kill pests, including insects (insecticides), weeds (herbicides), and fungi (fungicides). The USGS assesses the occurrence and behavior of pesticides in streams, lakes, and groundwater and the potential for pesticides to contaminate our drinking-water supplies or harm aquatic ecosystems.

The USGS works to monitor and assess how disease-causing pathogens enter our water and help those who manage drinking and wastewater facilities prevent and treat these viruses, bacteria, algal toxins, and other microorganisms.